Luminaires with automated and remotely controllable functionality are well known in the entertainment and architectural lighting markets. Such products are commonly used in theatres, television studios, concerts, theme parks, night clubs, and other venues. A typical product will commonly provide control over the pan and tilt functions of the luminaire allowing the operator to control the direction the luminaire is pointing and thus the position of the light beam on the stage or in the studio. Typically, this position control is done via control of the luminaire's position in two orthogonal rotational axes usually referred to as pan and tilt. Many products provide control over other parameters such as the intensity, color, focus, beam size, beam shape, and beam pattern. The beam pattern is often provided by a stencil or slide called a gobo which may be a steel, aluminum, or etched glass pattern.
FIG. 1 illustrates a typical multiparameter automated luminaire system 10. These systems commonly include a plurality of multiparameter automated luminaires 12 which typically each contain on-board a light source (not shown), light modulation devices, electric motors coupled to mechanical drive systems, and control electronics (not shown). In addition to being connected to mains power either directly or through a power distribution system (not shown), each automated luminaire 12 is connected in series or in parallel via data link 14 to one or more control desks 15. The automated luminaire system 10 is typically controlled by an operator through the control desk 15.
FIG. 2 illustrates a prior art automated luminaire 12. A lamp 21 contains a light source 22 which emits light. The light is reflected and controlled by reflector 20 through optical devices 26, which may include dichroic color filters, effects glass, and other optical devices well known in the art, and then through an aperture or imaging gate 24. Optical components 27 are imaging components and may include gobos, rotating gobos, an iris, and framing shutters. The final output beam may be transmitted through output lens 31. Output lens 31 may be a short focal length glass lens or equivalent Fresnel lens as described herein. Either optical components 27 or output lens 31 may be moved backwards and forwards along the optical axis (as shown by arrows 27a and 31a, respectively) to provide focus adjustment for the imaging components.
There is a need for an improved lens system for an automated luminaire which provides easy and rapid focus adjustment without compromising the automated movement of the automated luminaire.